1. Field of the Invention
The present invention relates to a fuel dispensing system for use in delivering fuel to a vehicle and, more particularly, to a sensor assembly integrated with the flowmeter that utilizes a Hall-effect device to measure the rotational velocity of the flowmeter rotor and hence the fuel flow rate by detecting recesses exhibiting magnetic properties that are formed in the rotor surface.
2. Description of the Related Art
Various configurations have been proposed that aim to measure the flow rate of fuel that is being communicated through the fuel line of a fuel dispensing system. In one conventional form, the measuring apparatus includes an arrangement of two pick-up devices each coupled to the flowmeter spindle shaft in a manner suitable for monitoring the rotational activity and direction of motion of the shaft so as to acquire signals representative of the rotational velocity of the shaft. Because the pick-up operation involves establishing at least two points of monitoring engagement with respect to the shaft, it is necessary that separate bore channels be formed into the rotor housing so as to accommodate each one of the pick-up devices. The drawbacks to this configuration involve the use of at least two pick-up devices and the installation requirement relating to the formation of separate mounting holes.
In another conventional apparatus, the flowmeter is modified for attachment to a sensor assembly that is configured within a separate housing structure. A disk is coaxially mounted at the end of the spindle shaft and is provided with magnets positioned at a circumferential portion thereof. The disk and accompanying magnets therefore move in tandem with the rotation of the spindle shaft. A pair of Hall-effect sensors are provided within the separate housing structure and are suitably positioned with respect to the mounted disk so as to be able to detect the rotation of the shaft by virtue of the coupling relationship a established with the magnets as they rotate with the disk. Among its disadvantages, this type of measurement apparatus requires a customized sensor design in addition to the utilization of an additional mounting disk and the construction of a separate sensor housing unit for attachment to the flowmeter.
According to the present invention there is provided an assembly for use in a fuel dispensing system that utilizes a Hall-effect pick-up device integrated within a flowmeter to provide a measure of the rotational velocity of the rotor and hence the flow rate of fuel being transmitted through the fuel line. The rotor is modified to include at least one discontinuity defined in its outer surface, preferably in the form of a recessed area. These recessed areas are suitably provided so as to exhibit magnetic properties. The Hall-effect sensor includes a first and second Hall-effect element each generating a respective channel signal that is representative of the rotational velocity of the rotor. The Hall-effect sensor is suitably arranged with respect to the rotor so as to enable each one of the recessed areas to exert a characteristic magnetic influence upon the Hall-effect sensor during shaft rotation. In particular, the Hall-effect elements each detect the occurrence of each one of the recessed areas as it rotates therepast during shaft rotation and generates within its respective channel signal a representation of each such detected occurrence. These representations will typically take the form of a signal variation that is attributable to the variation in magnetic field experienced by the Hall-effect element as the recessed area rotates past it. The rate of generation of such magnetic field variations (as manifested in the sensor channel signals as corresponding variations in a signal parameter or characteristic, i.e, voltage) is representative of the rotational velocity of the rotor. A processor provides a measure of the fuel flow rate as derived from the sensor channel signals. This sensor configuration requires the formation of only a single mounting hole for accommodating the mounting attachment of the pick-up device to the flowmeter. A temperature sensor is preferably integrated with the Hall-effect sensor to provide a measure of the fuel temperature.
The invention, in one form thereof, is directed to an assembly for use in a fuel dispensing system. The assembly comprises a flowmeter coupled to a fuel line of the fuel dispensing system and including a rotor; and a pick-up assembly integral with the flowmeter and operative to provide a measure of the flow rate of fuel in the fuel line as a function of the rotational velocity of the rotor. The pick-up assembly comprises a Hall-effect sensor arranged proximate the rotor and operative to provide at least one output signal representative of the rotational velocity of the rotor. The rotor includes at least one recessed area formed therein exhibiting magnetic properties and being suitably arranged with respect to the Hall-effect sensor so as to enable the at least one recessed area to exert a characteristic magnetic influence upon the Hall-effect sensor during rotor rotation. The assembly further comprises a processor that is operative to provide a measure of the fuel flow rate in the fuel line as derived from the at least one output signal provided by the Hall-effect sensor.
The Hall-effect sensor, in one form thereof, further includes a first Hall-effect element generating a first channel signal representative of the rotational velocity of the rotor; and a second Hall-effect element generating a second channel signal representative of the rotational velocity of the rotor. The first channel signal generated by the first Hall-effect element and the second channel signal generated by the second Hall-effect element preferably have a predetermined phase-shift therebetween. In one form, the first Hall-effect element and the second Hall-effect element are arranged relative to one another in a spaced-apart relationship that is sufficient to cause a 90 degree phase-shift between the respective first channel signal and the second channel signal generated thereby. The processor evaluates the first channel signal generated by the first Hall-effect element and the second channel signal generated by the second Hall-effect element to derive the measure and flow direction of the fuel flow rate.
The at least one recessed area further comprises, in one form thereof, a set of three recessed areas disposed in spaced-apart relationship about the circumferential surface of the rotor. The Hall-effect sensor, in one form thereof, is disposed at least in part within a housing structure mounted to the flowmeter, wherein such flowmeter mounting is characterized by the use of a single mounting space defined in the flowmeter for receiving, at least in part, the housing structure. The assembly further includes, in one form thereof, a temperature sensor integrally associated with the pick-up assembly and which is suitably arranged with respect to the fuel line of the fuel dispensing system to operatively provide a measure of the fuel temperature.
The invention, in another form thereof, relates to an assembly for use in a fuel dispensing system. The assembly comprises a flowmeter coupled to a fuel line of the fuel dispensing system and including a rotor, wherein such rotor includes at least one discontinuity provided in the circumferential surface thereof to define a discontinuous portion of the rotor; a detection means, which is disposed proximate the rotor at the discontinuous portion thereof, for detecting the is occurrence of each one of the at least one rotor discontinuity rotating therepast and for generating at least one signal representative of the rotational velocity of the rotor as derived from the rate of detected occurrence of at least one of the at least one rotor discontinuity; and a means for providing a measure of the flow rate of fuel in the fuel line as derived from the at least one signal generated by the detection means. In a preferred form, each one of the at least one rotor discontinuity exhibits magnetic properties.
The detection means, in one form thereof, further includes a Hall-effect sensor suitably arranged with respect to the at least one rotor discontinuity so as to enable each one of the at least one rotor discontinuity to exert a characteristic magnetic influence upon the Hall-effect sensor during rotor rotation. Each one of the at least one rotor discontinuity further includes, in one form thereof, a recessed area formed in the rotor.
The Hall-effect sensor further includes, in one form thereof, a first Hall-effect element generating a first channel signal representative of the rotational velocity of the rotor; and a second Hall-effect element generating a second channel signal representative of the rotational velocity of the rotor. The first channel signal generated by the first Hall-effect element and the second channel signal generated by the second Hall-effect element have a predetermined phase-shift therebetween. In a preferred form, the first Hall-effect element and the second Hall-effect element are arranged relative to one another in a spaced-apart relationship that is sufficient to cause a 90 degree phase-shift between the respective first channel signal and the second channel signal generated thereby.
The at least one rotor discontinuity further includes, in one form thereof, a set of three recessed areas formed in the rotor and disposed in spaced-apart relationship about the circumferential surface of the rotor. Accordingly, for each complete rotation of the rotor, each one of the first channel signal and the second channel signal generated respectively by the first Hall-effect element and the second Hall-effect element includes a representation of the detected occurrence of each one of the set of three recessed areas formed in the rotor.
The Hall-effect sensor, in one form thereof, is disposed at least in part within a housing structure mounted to the flowmeter, wherein such flowmeter mounting is characterized by the use of a single mounting space defined in the flowmeter for receiving, at least in part, the housing structure. The assembly further includes, in one form thereof, a temperature sensor integrally associated with the detection means and being suitably arranged with respect to the fuel line of the fuel dispensing system to operatively provide a measure of the fuel temperature.
The invention, in another form thereof, is directed to an assembly for use in a fuel dispensing system. The assembly comprises a flowmeter coupled to a fuel line of the fuel dispensing system and including a rotor, wherein such rotor includes at least one discontinuity defined in the outer surface thereof and which exhibits magnetic properties; a Hall-effect sensor arranged relative to the rotor in a manner sufficient to enable the development of an inductive coupling relationship between each one of the at least one rotor discontinuity and the Hall-effect sensor during operative rotation of the rotor. The Hall-effect sensor comprises a first Hall-effect element generating a first channel signal representative of the rotational velocity of the rotor and a second Hall-effect element generating a second channel signal representative of the rotational velocity of the rotor, wherein the first channel signal and the second channel signal have a predetermined phase-shift therebetween. The assembly further comprises a processor that is operative to provide a measure of the flow rate of fuel in the fuel line based upon the first channel signal and the second channel signal generated respectively by the first Hall-effect element and the second Hall-effect element.
The at least one rotor discontinuity further comprises, in one form thereof, a set of three recessed areas disposed in spaced-apart relationship about the outer surface of the rotor. The Hall-effect sensor, in one form thereof, is disposed at least in part within a housing structure mounted to the flowmeter, wherein such flowmeter mounting is characterized by the use of a single mounting space defined in the flowmeter for receiving, at least in part, the housing structure. The assembly further comprises, in one form thereof, a temperature sensor integrally associated with the Hall-effect sensor and which is suitably arranged with respect to the fuel line of the fuel dispensing system to operatively provide a measure of the fuel temperature.
One advantage of the present invention is that a single Hall-effect sensor generating a first and second channel signal as disclosed herein is sufficient to measure the rotational velocity and flow direction of the flowmeter shaft.
Another advantage of the present invention is that the sensor configuration requires the formation of only a single mounting hole for accommodating the mounting attachment of the pick-up device to the flowmeter.
A further advantage of the invention is that the rotor may be easily adapted to facilitate its use with the Hall-effect sensor disclosed herein without imposing any limitation on its functionality within the flowmeter, namely by providing recessed areas in the rotor outer surface that exhibit magnetic properties.